Beam switching tube counting circuit with single-ended drive



Feb. 2, 1965 A. SOMLYODY BEAM SWITCHING TUBE COUNTING CIRCUIT WITH SINGLE-ENDED DRIVE Filed Dec. 31, 1962 wow-Dom wmJE INVENTOR. AR PAD SOMLYODY ATTORNEY 3,168,676 BEAM SWITCHING TUBE COUNTING CIRCUIT WITH SINGLE-ENDED DRiVE Arpad Somlyody, Raritan, N.J., assignor to Burroughs Corporation, Detroit, Mich, a corporation of Michigan Filed Dec. 31, 1962, Ser. No. 243,600

4 Claims. (Cl. 315--8.5) This invention relates to electronic counting circuits and particularly to counting circuits using multi-position magnetron beam switching tubes as the counting elements thereof.

Magnetron beam switching tubesare counting devices which include an electron-emitting cathode and ten groups of electrodes, each of which is adapted to receive an electron beam from the cathode and to provide an output signal therefrom. Each group of electrodes includes a target electrode which receives an electron beam and produces an output signal therefrom, an auxiliary collector electrode, a spade electrode which forms and holds an electron beam on its associated target electrode, and a switching electrode which may be used to switch an electron beam from one group of electrodes to the next to perform the counting operation.

In the operation of beam switching tubes'as counters, counting pulses are applied to a tube in either a singleended or double-ended drive arrangement. t In a doubleended drive circuit, the switching electrodes of a tube are connected in two sets, with alternate electrodes in each set, and each set is connected to one of the outputs of a flip-flop. As the flip-flop changes state, an electron beam is switched by one position in the tube. In a single-ended drive arrangement, a single source of pulses is connected to all of the switching electrodes connected together in common. Such a single-ended drive arrangement is generally preferred, among other things, for its economy and simplicity. However, in the past, in singleended drive circuits, it was necessary to provide driving pulses which had a measured time duration to insure that each pulse would cause an electron beam to switch by only one position at a time. Such time-measured pulses are known as quantized pulses.

Thus, the objects of the present invention are concerned with the provision of an improved counter circuit using a magnetron beam switching tube as the counting element thereof, the circuit including a single-ended drive arrangement which does not require quantized driving pulses.

Briefly, a counter circuit embodying the invention uses a multi-position magnetron beam switching tube as the counting element thereof. In the tube, each spade electrode is coupled to the adjacent leading spade electrode through a selected coupling circuit which operates with the various applied potentials so that, with an electron beam flowing to a tube position, a counting pulse applied to all of the spade electrodes can affect only the spade electrode next to the tube position to which the electron beam is flowing. Thus, the beam is caused to switch by one position to the next leading position. Each counting pulse applied thus causes an electron beam to switch by one position. The coupling circuit elements are such that the counting pulses need not be quantized pulses.

The single figure of the drawing is a schematic representation of a circuit embodying the invention.

The circuit shown in the drawing is particularly suited for use with magnetron beam switching tubes such as the type 6700 tube and with similar devices sold by the Burroughs Corporation and known as Beam-X switches. These devices are cylindrical in form, but they are shown schematically in linear form as tube 10 in FIG. 1. The tube 10 has an envelope 12 which contains a central cathode 14 and ten groups of electrodes spaced radially equi- United States Patent M 3,158,676 Patented F eh. 2, 1965 2 distantly from and surrounding the cathode. For simplicity, only four groups of electrodes are shown numbered 0, 1, 2, and 3. Each group of electrodes includes. a spade electrode 16 and a target electrode 18, with each spade electrode serving to form and hold an electron beam on its corresponding target electrode which itself provides an output signal from the beam. A switching electrode, used for switching an electron beam from position to position, is also included in each group of elec trodes. In the Beam-X switch, an auxiliary collector electrode is also provided. However, the switching electrodes and collector electrodes are not required in the present invention, so they are not shown in the drawing.

The tube 10 also includes suitable means (not shown) for providing an axial magnetic field which operates with electric fields within the tube to form an electron beam and switch it from one group of electrodes to the next. Such means may be external permanent magnet or internal magnets or the like. The electrodes themselves may be magnets. The direction in which an electron beam is urged, that is clockwise or counter-clockwise, is called the leading direction, and is always the same and is determined by the orientation of the electric and magnetic fields.

In the circuit of the drawing, the cathode 14 is connected to a reference potential such as ground, and the target electrodes 18 are connected though suitable load resistors 22 to a bus 28 which is connected to a positive DC. power source Vt of about 200 volts. In addition, volts. Diodes 76 and source Vc are optional aids for imconnection to a suitable utilization device or circuit.

According to the invention, each spade electrode 16 is coupled through two spade load resistors 36 and 38 to a bus 40, one end of which is connected to a positive DC. power source Vs of about 200 volts. The junction 46 of resistors 36 and 38 is also coupled through a separate capacitor 50 to a bus 56 which is connected to a source 60 of negative counting step pulses or waves 64. Preferably, pulses 64 have a sharp leading edge; their time duration is not critical. Each junction point 46 is also coupled through a diode 70, oriented as shown, to the next leading spade, and each spade is coupled through a diode 76, oriented as shown, to a bus which is connected to a positive DC. power source Vc of about 60 volts. Diodes 76 and source Vc are optical aids for improving the speed of operation of the circuit. In each case, resistor 36 and capacitor 50 comprise a diiferentiating network which can convert waves 64 into sharp pulses which appear at the cathode of diodes 70.

In operation of the circuit, with the supply voltages indicated and assuming that an electron beam is in the 1 position, then the 1 spade and the anode of diode 70A are at ground potential. The junction point of the load resistors 36 and 38 coupled to the "0 spade electrode and the cathode of diode 70A are at about volts. The junction point 46 of the resistors 36 and 38 coupled to the "1 spade is at about 80 volts, as is the cathode of the associate diode 70B. The 2 spade and the anode of diode 70B are at 60 volts. All of the other electrodes are at such potentials that the other diodes 70 are strongly reverse biased. When a negative counting pulse 64 is applied to the bus 56 and it appears at all of the capacitors 50, it can be coupled only through the diode 70B which is properly biased. The other diodes 70 are too heavily biased in the reverse direction. Thus, the counting pulse is coupled through diode 703 to the 2 spade and the beam is switched from the "1 position to the "2 position. With the beam in the 2 position, the junction 46 of the 2, spade resistors 36 and 38 is lowered to about 80 volts, which provides 80 volts on the cathode of the associated diode 700. As described above, the anode of diode 70C will assume about 60 volts. All of the other diodes 7b are heavily reverse biased. Thus, the next counting pulse can be coupled only through diode 70C to the next spade, the 3 position. In this Way, the electron beam is caused to be switched from one position to the next and thus execute the desired counting operation.

The invention thus provides an improved counting circuit utilizing magnetron beam switching tubes and singleended drive therefor in which the driving waves or pulses are not critical with respect to time duration.

What is claimed is:

1. A counter circuit including an electron beam switching tube having a cathode and a plurality of groups of electrodes; each group comprising a tube position to which an electron beam can flow from said cathode and including a target electrode which receives an electron beam and produces an output signal therefrom, and a spade electrode which holds an electron beam on its associated target electrode;

first means coupling said spade and target electrodes to operating potentials;

second means coupling each spade electrode to the next leading spade electrode; and

a signal input line coupled to each spade electrode;

said second means including a differentiating circuit;

the operating potentials and said second means being such that when an electron beam flows to a tube position, only the next leading spade electrode which is coupled thereto is able to receive an input signal from said input signal line.

2. The circuit defined in claim 1 wherein said second means includes a resistor and capacitor, connected as a differentiating circuit, and a diode.

3. The circuit defined in claim 1 wherein said second means includes a resistor and capacitor, connected as a differentiating circuit, and a diode, said capacitor also being coupled to said signal input line.

4. The circuit defined in claim 1 and including a source of signal pulses coupled to said signal input line, said signal pulses comprising step waves having a sharp leading edge.

References Cited in the file of this patent UNITED STATES PATENTS 3,092,752 Wolfe June 4, 1963 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3,168 ,676 February 2 1965 Arpad Somlyody It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2 line 18 after "be" insert an line 30, for "volts Diodes 76 and source Vc are optional aids for im-" read an auxiliary output tap 34 is provided at each target for Signed and sealed this 6th day of July 1965 (SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

